Embodiments of the invention relate to the field of inserting goods into covers, more specifically to an apparatus and a method for inserting one or more goods into a moveable cover, for example an envelope.
In the art various approaches for inserting one or more goods into a cover, such as an envelope, are known. In accordance with one approach during the filling process an envelope is stopped and only the goods are moved to be inserted into the envelope. The problem with this kind of inserters is that they operate in a start/stop mode meaning that when filling the one or more goods the envelope needs to be stopped and, after completing the filling process, the envelope is moved out of the filling position and a following envelope is arranged in the filling position and stopped again to allow filling the one or more goods into this new envelope. The problem with this kind of inserter is that the throughput, i.e., the number of envelopes that can be filled with one or more goods during a predetermined period of time, for example within an hour, is limited due to the necessity of decelerating, stopping and accelerating the envelopes during the filling process. Further, the mechanical wear and stress of the respective parts of the inserter, the goods and/or the envelopes is quite high.
Another approach for inserting one or more goods into a cover is to move both the one or more goods and the cover during the filling process. Such an approach is e.g. described in DE 42 05 197 A1, WO 94/27832 A1, U.S. Pat. No. 4,525,986 A, U.S. Pat. No. 3,858,381 A, U.S. Pat. No. 4,817,368 A, U.S. Pat. No. 5,430,990 A and WO 2002/096670 A1. The transport directions of the one or more goods and an envelope extend parallel in the same direction, however, the filling process is such that the one or more goods, the envelope or both are moved angular with respect to the transport direction towards each other. At the beginning of a filling path the envelope and the one or more goods travel side by side with the one or more goods and/or the envelope being moved angular towards each other. Eventually, the goods and the envelope meet such that due to the angular movement of the goods, they are filled into the envelope. In case filling pockets are used for each of the goods, as e.g. described in WO 94/27832 A1 or U.S. Pat. No. 5,430,990 A, a plurality of individual pockets are required, which need to be returned to the starting point so that an additional transport is needed which increases the number of necessary parts even further as well as the costs. Yet another problem of this kind of filling process are the high kinematic forces that are applied to the envelope and the goods due to the angular transport. Further, the necessity to provide parallel transports for the goods and for the envelope increases the costs, for example due to the fact that at each position respective guidings are required. In terms of the required installation space, quite a lengthy set up is required as well as additional space for placing two transports in parallel. Also the time and efforts for changing the format is high (e.g. it is necessary to modify a plurality of elements of the pockets for adjustment to the new format) and, basically, these approaches are not flexible with regard to the format processed. In addition, due to the many parts that move, the operation of the device is quite noisy.
Yet another approach teaches to move the one or more goods and the cover or envelope along a common filling or inserting path in such a way that the envelope is moved at least a little bit slower than the one or more goods so that along the filling path the one or more goods eventually “overtake” the envelope, however, since the envelope has its envelope throat opened, this process results in the filling of the goods into the envelope. Such an approach is, for example, described by U.S. Pat. No. 3,423,900 or EP 1 418 840 A1. In accordance with these approaches during the filling process the envelope is moved continuously along the filling path, wherein the transport of the envelope along the filling path is achieved by filling elements that are provided on both sides of the filling path and engaged with the lateral inside edges of the envelope body. However, the filling elements are inserted into the stopped envelope and moving the filling elements along the inserting path will cause the transport of the envelope along the inserting path. The drawback of this approach is that the filling elements cause the transport of the envelope so that a precise placement of these envelopes onto the filling elements is required. Therefore, handling of the envelopes becomes difficult in case of deviations in the format, e.g. due to manufacturing tolerance which may be in the range of about 1.5 mm. Such tolerances in the width direction of the envelope result in the envelope to be either clamped on the filling elements or to be held by the filling elements loosely; in either case no reliable transport of the envelopes is possible. In case a clamping occurs the removal of the filled envelope from the filling elements is difficult. Further, it is not possible to actively decelerate the transport mechanism as this would result in the envelopes to slide off the filling elements. Also, there is no flexibility allowing for an easy change of the formats processed. Yet another problem with the approach of U.S. Pat. No. 3,423,900 or EP 1 418 840 A1 is that, as mentioned above, tolerances of the dimensions of the envelopes are not considered. Since the filling elements will also provide for the transport of the envelope they need to be adjusted dependent on the envelope. A further disadvantage is that removal of the envelope from the filling element by the goods transport is difficult in case the goods comprise only a single sheet of paper. In this case, the force applied by the goods transport may damage the sheet before a movement of the envelope by the filling element is started. Further, there is no possibility control how far the filling element moves into the envelope, e.g. dependent on the thickness of the goods, rather independent of the thickness of the goods to be inserted, the filling element must be inserted completely into the envelope, i.e., it is always inserted up to a fixed position so that the envelope is always spanned irrespective of the thickness of the goods to be inserted. Further, in accordance with EP 1 418 840 A1 an envelope flap is held by a suction rail which decelerates the envelope so that it is maintained in contact with the filling element, however, there is no control or regulation possible. Further, there are difficulties when removing the filled envelope using the goods transport, since the provision of the additional suction rail and the decelerating action thereof requires to apply a high force to the envelope for removing it from the filling elements which, naturally, results in damages and possible jams even after the filling process has already been completed. Further, this approach requires high mechanical efforts, for example due to the required mechanical coupling of all drives via a single main shaft.
Another problem with approach described in U.S. Pat. No. 3,423,900 or EP 1 418 840 A1 is that a central portion of the envelope sags because filling elements engage with the opposite lateral edges of the envelope. In case of larger formats, e.g. formats having a large lateral dimension, this is a serious problem as the one or more goods to be inserted may collide with the sagging envelope side resulting in jams so that no reliable filling is possible.
Yet another problem with approach described in U.S. Pat. No. 3,423,900 or EP 1 418 840 A1 is that the goods and the envelope are moved so that it is necessary to carefully control the motion of each element to avoid a gap between a leading edge of the goods and an edge of an envelope flap. In case such a gap is generated the goods and the envelope flap may collide. This is a problem being specifically problematic with short flaps.